// Copyright 2017 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef V8_LIBPLATFORM_DEFAULT_WORKER_THREADS_TASK_RUNNER_H_
#define V8_LIBPLATFORM_DEFAULT_WORKER_THREADS_TASK_RUNNER_H_

#include <vector>

#include "include/libplatform/libplatform-export.h"
#include "include/v8-platform.h"
#include "src/base/platform/mutex.h"
#include "src/base/platform/platform.h"
#include "src/libplatform/delayed-task-queue.h"

namespace v8 {
namespace platform {

    class V8_PLATFORM_EXPORT DefaultWorkerThreadsTaskRunner
        : public NON_EXPORTED_BASE(TaskRunner) {
    public:
        using TimeFunction = double (*)();

        DefaultWorkerThreadsTaskRunner(uint32_t thread_pool_size,
            TimeFunction time_function);

        ~DefaultWorkerThreadsTaskRunner() override;

        void Terminate();

        double MonotonicallyIncreasingTime();

        // v8::TaskRunner implementation.
        void PostTask(std::unique_ptr<Task> task) override;

        void PostDelayedTask(std::unique_ptr<Task> task,
            double delay_in_seconds) override;

        void PostIdleTask(std::unique_ptr<IdleTask> task) override;

        bool IdleTasksEnabled() override;

    private:
        class WorkerThread : public base::Thread {
        public:
            explicit WorkerThread(DefaultWorkerThreadsTaskRunner* runner);
            ~WorkerThread() override;

            // This thread attempts to get tasks in a loop from |runner_| and run them.
            void Run() override;

        private:
            DefaultWorkerThreadsTaskRunner* runner_;

            DISALLOW_COPY_AND_ASSIGN(WorkerThread);
        };

        // Called by the WorkerThread. Gets the next take (delayed or immediate) to be
        // executed. Blocks if no task is available.
        std::unique_ptr<Task> GetNext();

        bool terminated_ = false;
        base::Mutex lock_;
        DelayedTaskQueue queue_;
        std::vector<std::unique_ptr<WorkerThread>> thread_pool_;
        TimeFunction time_function_;
    };

} // namespace platform
} // namespace v8

#endif // V8_LIBPLATFORM_DEFAULT_WORKER_THREADS_TASK_RUNNER_H_
